音頻科普:暗光纖網(wǎng)絡(luò)有助于勘測地震活動
發(fā)布時間:2021-06-29
瀏覽次數(shù):2145
音頻科普:暗光纖網(wǎng)絡(luò)有助于勘測地震活動

?Scientists are exploring the use of fiber-optic cables—like the ones that form the backbone of the internet—to monitor earthquakes.光纖電纜是龐大網(wǎng)絡(luò)的基礎(chǔ),科學(xué)家們一直在探索測地震應(yīng)用。
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撰文\播音:朱莉婭·羅森(Julia Rosen
翻譯:陳美娟
審校:潘磊
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When an earthquake hits or a volcano erupts, scientists traditionally record the shaking using a specially designed instrument called a seismometer. These sensors are extremely sensitive, but they’re also expensive and distributed unevenly around the world. So scientists are working on another strategy to monitor earthquakes: using fiber-optic cables—like the ones that form the backbone of the internet.
當(dāng)一場地震襲擊或是火山噴發(fā)來臨時,一般,科學(xué)家會使用一種叫做地震儀的特制儀器來記錄震動情況。這些感受器對震動極為敏感,但同時它們也造價昂貴,在世界各地的分布數(shù)量不均。因此科學(xué)家們正研究另一種手段來監(jiān)測地震:利用光纖電纜——很像那些作為互聯(lián)網(wǎng)基礎(chǔ)設(shè)施的電纜。
“So the motions are very clear. Specifically, you can see the arrival of different bits of the seismic energy from the location at which the earthquake occurred. So the p wave and the s wave, and the different phases that move out from the site of rupture in the earth, are used by seismologists to locate the event. And so we can detect the important pieces of information above the noise using the fiber-optic cable and then, in that way, the fiber-optic measurement is just as good as a seismometer.”
震動情況會非常清楚。特別地,你能看到來自不同地震發(fā)生點的地震能量是如何匯集的。從地球內(nèi)部裂點出發(fā)的縱波與橫波以及傳播的不同介質(zhì)可以被地震學(xué)家用來定位災(zāi)害事件。而通過光纖電纜探測,我們能去除地震背景干擾獲得這些重要信息。這么看,光纖電纜勘測方法和地震儀一樣有效。
Nate Lindsey, a PhD student and seismologist at the University of California, Berkeley. Here’s how it works: the scientists basically take a snapshot of the fiber by shining a laser down it and measuring the photons that bounce back after scattering off of small cracks and impurities in the glass. By doing this tens of thousands of times a second, the researchers can record how the cable deforms as seismic waves pass through it.
Nate Lindsey是加州大學(xué)伯克利分校的博士生,也是一名地震學(xué)家。它是這樣工作的:科學(xué)家通過向地底激光照射,測量光子在纖維裂紋和玻璃纖維內(nèi)部雜質(zhì)散射后的回彈量——給光纖拍快照。通過每秒上百萬次的測量,研究者記錄下地震波穿過時光纖電纜的變形情況。
So far, Lindsey?s team has tested the technique in optical fibers they installed themselves in Fairbanks, Alaska, and around the Bay Area. They got promising results. But their ultimate goal is to capitalize on the vast network of unused cables—known as dark fiber—that’s already been installed by telecommunications providers for future use. Dark fiber covers much of the country, and stretches across the ocean basins—which are hard to study using traditional seismometers.
目前,Lindsey的團隊正在費爾班克斯、阿拉斯加以及舊金山灣區(qū)他們自己搭建起的光纖電纜中測試這項技術(shù)。他們得到了不錯的結(jié)果。他們的最終目標(biāo)是充分利用龐大的未使用的光纖網(wǎng)絡(luò)——所謂的暗光纖——通訊公司為未來使用預(yù)鋪設(shè)了大片。暗光纖覆蓋了國家大部分地區(qū),而且線路通過洋盆——是用傳統(tǒng)方法難以勘測的區(qū)域。
“To put the same sensor near a volcano that occurs offshore requires infrastructure to deploy the sensor, like a big boat. It also requires a tethered cable, a battery. The sensor has to be waterproof, obviously. It’s also very corrosive underneath the ocean, and so there’s been a limitation of our ability to study offshore volcanoes. Similarly faults. Earthquake processes are understood based on faults that are on land.”
要想將相同的探測器放置在近海的火山附近,需要能放置探測器的基礎(chǔ)設(shè)施,比如一條大船。這還需要用繩固定的電纜和電池。探測器必須是防水的。海水環(huán)境腐蝕作用很強,所以我們研究近?;鹕交顒佑蟹N種限制。同樣地質(zhì)斷層研究也有很多限制。而地震過程的理解基于陸上斷層相關(guān)研究。
Offshore cables could also improve earthquake early warning systems in places like the Pacific Northwest, where big, dangerous earthquakes actually occur under the ocean.
近海電纜還可能改進(jìn)地震預(yù)警系統(tǒng),例如在太平洋西北岸處,大規(guī)模嚴(yán)重的地震實際上都發(fā)生于海底。
“We can record that earthquake more quickly and then provide a warning that much quicker. So it might be a second or two seconds more that this fiber-optic technology provides.”
我們可以更快地記錄地震活動,然后更快地提供地震預(yù)警。這種光纖電纜技術(shù)能夠給我們珍貴的一到兩秒鐘。
Lindsey is?presenting his work?this week at the fall meeting of the American Geophysical Union in New Orleans. The results were also published recently in Geophysical Research Letters. If the technique proves reliable, Lindsey says it could usher in a whole new way of studying earthquakes and volcanoes. All that dark fiber may shed light on the Earth beneath our feet.
在于新奧爾良召開的美國地球物理學(xué)聯(lián)合會秋季會議上,Lindsey展示了他的研究成果。這項研究成果最近被刊登在了《地球物理研究快報》上。一旦這項技術(shù)被證實是可靠的,Lindsey認(rèn)為這引領(lǐng)一種對地震與火山活動的全新研究方式。暗光纖將揭開我們腳下地球的奧秘。
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注釋:Dark?fiber,國外的專業(yè)術(shù)語直譯為暗光纖” ,國內(nèi)習(xí)慣稱之為裸光纖” ,即在管道中尚未被傳輸或數(shù)據(jù)設(shè)備點亮的光纖。



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